VHDL Issue Number:      0130
Classification:         Language Definition Problem
Language Version:       VHDL-87
Summary:                There's no difference between an input type conversion
                        function for a non-signal IN parameter and just a
                        function invocation expression as the actual
                        designator.
Related Issues:         None.
Relevant LRM Sections:  4.3.3.2
Key Words and Phrases:  Conversion Functions, Association Lists
Current Status:         ISAC-Approved
1076-1993 Disposition:  Closed (All Issues Completely Addressed)
Disposition Rationale:  LRM is clear now, discussed in 4.3.2.2.
Superseded By:          N/A
-----------------------
Date Submitted:         1989/06/21
Author of Submission:   Rod Farrow
Author's Affiliation:   Vantage Analysis Systems, Inc.
Author's Post Address:  42808 Christy St., Suite 200
                        Fremont, CA   94538
Author's Phone Number:  (415) 659-0901
Author's Fax Number:    
Author's Net Address:   N/A
-----------------------
Date Analyzed:          1991/11/16
Author of Analysis:     Paul Menchini (mench@clsi.com)
Revision Number:        $Revision: 1.9 $
Date Last Revised:      $Date: 1995/05/13 19:34:42 $


Description of Problem
----------------------
There is no difference between an input type conversion function for a non-
signal IN parameter and just a function-invocation-expression as the actual
designator.  It is ambiguous to distinguish the two and the effect is the same
in any event.


Proposed Resolution
-------------------
For generic map aspects and subprogram association lists our current approach
is to interpret all input conversion functions as simply function application.


VASG-ISAC Analysis & Rationale
------------------------------
The author's problem statement is nearly correct.  There *is* a difference
between a type-converted actual and a function call expression when the class
of the formal is either signal or variable.  However, the author is correct in
stating that there is no semantic difference when the formal's class is
constant.

We assume in the case of the association of constants that the actual is never
type-converted.


VASG-ISAC Recommendation for IEEE Std 1076-1987
-----------------------------------------------
When associating constants, never interpret the actual has having a type
conversion function.


VASG-ISAC Recommendation for Future Revisions
---------------------------------------------
Add language to this effect in Section 4.3.3.2.